This invention relates in general to communication systems, and more specifically to a method and apparatus for adapting a routing map for a wireless communications network.
The traditional approach used for terrestrial wireless communication networks such as cellular networks consists of dividing the desired coverage area into a set of overlapping regions, where all of the subscribers within each region are served from a single transceiver known as a base station using a point-to-multipoint (PMP) or one-to-many approach. One of the problems with a PMP architecture is that it becomes more difficult to establish links directly between a given subscriber radio and the base station as the transmission carrier frequency increases, which poses a problem for future wireless networks since they are increasingly being deployed at higher carrier frequencies.
Other problems are the economic burdens associated with deploying a system since large costs are incurred during deployment of the infrastructure before any revenue can be raised to offset those expenses. Additionally there are extensive problems of coordination and planning and expense associated with expanding such systems. To avoid or address these problems to one extent or another, a new type of network architecture known as xe2x80x9cmeshxe2x80x9d architecture is being explored. Some systems are being proposed and deployed for providing relatively broadband packet data services to residential customers. Some fixed wireless systems or networks that are part PMP and part mesh network have been proposed and may be referred to as hybrid systems or networks. These systems may be initially deployed in part as PMP systems with each of the communications units in the PMP arrangement also acting as wireless network access points for clusters of communications units operating in a mesh network arrangement.
In a mesh architecture a multiplicity of communications units are deployed, normally one or more per household or business and operate in an ad-hoc peer to peer fashion to establish links where possible and as required among each of a given units neighbors. For example, units can establish links or paths with several other units particularly where as is typical the units employ an omni-directional antenna. Some units can employ a directional antenna to limit their ability to see (establish links with) units that are not in the direction of their antenna while improving there ability to see units in the direction of the antenna. Some units typically operate as hybrid units or in a hybrid mode, partly in a PMP mode and partly in a mesh mode. These units may be coupled to a base station using a PMP link or path where the base station acts as a wide area network (WAN) access point. The same unit will operate in a mesh mode for and with other units in its vicinity effectively representing a network access point for the other units. This mesh network at the end of a PMP link is often referred to as a cluster.
Each or many of the communications units have the ability to relay communications signals from an originating communications unit to a target unit when these communications units are not able to create a direct communication link or path from one to the other unit. Information that is being communicated may be relayed or handed from communications unit to communications unit until it reaches the intended destination or target unit. Note: that if the direct link from one unit to another were interrupted by, for example a tree growing or new building being constructed, the inherent redundancy in the mesh architecture allows routing the information through a third unit or routing unit. In this fashion the infrastructure or backbone that is represented by the traditional base stations and supporting equipment is in a sense deployed as the system gains customers and begins to realize revenue.
However the mesh architecture or system and particularly the hybrid system can also experience problems. Note that all traffic to and from the WAN must pass through a relatively small number of units, namely those having access to the WAN. In the hybrid network all WAN traffic goes through the base station. The links from the base station are PMP links meaning that ordinarily only one link can be active at a time. If the units or wireless communications units (WCUs) at the end of these links are low data rate units at least in the PMP mode too many such links can adversely effect capacity or throughput from the base station. Conversely too few such PMP links can also adversely effect capacity as too much of the load is being pushed to few WCUs or wireless routers. Obviously better methods and apparatus for adapting routing maps in such wireless networks are needed.